Compensating contact finger



COMPENSATING CONTACT FINGER Filed July 29, 1952 @d 'l N INVENTR. Figi l` HARRY r-. woERNLEw A TTORNE'Y.

Patented Sept. 22, 1936 narran. sTATEs PATENT orrice 2,055,114 COMTENSATING CONTACT FINGER Application July 29, 1932, serial No. 625,611

4 claims. (c1. 20o-171) This invention relates to electric switch devices and more particularly to' la contact mechanism for a. switch device.

The invention has special reference to a switch device of the character in which a circuit is adapted to be controlled through a resiliently supported nger carried by one member and adapted to engage or disengage a plate contact fixed on another member, according to the relative movement'l between the two members.

A switch device having acontact mechanism of the above described character is disclosed in Patent No. 1,832,887, issued to me on November 24, 1931. In the construction disclosed in this patent, the contact nger is hinged to permit movement only in a direction toward the plate contact and it is intended that the parts of the hinge be tted suiiiciently close to form a part of the circuit controlled through the finger.

If in the above construction, there should be any misalignment of the contact finger and contact plate, a proper bearing between the brush on the iinger and the contact plate will not be obtained. A plurality of switches of this type are often mounted side by side in train Wire couplers and it is especially diicultlunder this condition to ensure the proper bearing between the several brushes and their respective platecontacts.

It has also been proposed to provide a hinged contact ringer in which the finger is adapted to turn slightly around its 'longitudinal axis, so that when the brush on the finger engages the contact plate, the brush can adjust itself to the contact plate and obtain a good bearing.`

With either of the aboveY or other types of hinged contact ngers, it is necessary to employ materials of good electrical conductivity, although it is difcult with such materials to provide a structure of adequate strength,`particularly where the contact ringer must be small.

In order to overcome the above diiiiculty, the principal `object of my invention -is to provide a hinged contact finger of the above type with a exible electrical conductcr which is adapted to 4electrically connect the hinged members of the contact linger so as to provide an electrical conductor which is independent of `the hinge.

By this constructionthe hinge portion of the contact member is not depended upon to conduct current and can thus be made of materials which i will provide adequate strength, while `at the same time ensuring electricalconductivity at all times, f

regardless lof the positions of the hinge "joint,

'Other-objects and advantages willappear in the Yto forces tending .to move it towards the right Fig. 4 is an inverted plan viewof the parts shown in Fig. 2; Fig. 5 is a plan View of the stationary 10 portion of the contact nger; Fig. 6 is a side elevation of the member shown in Fig. 5; Fig. 7 is an inverted plan view of the member shown in Fig. 5; Fig. 8 is a plan View of a-clip; Fig. 9 is a side elevation of the clip shown in Fig. 8; Fig. l0 is a side` `15 elevation oi the linger contact brush; Fig. ll'is an inverted plan view of the finger contact brush;

Fig. 12 is a plan View of a portion of the brush carrying member; and Fig. 13 is a plan view of the cable tip at thebrush end of the hinge shunt.

As shown in the drawing, the switch device com- 20 prises two relatively movable members or insulating `blocks l and 2., the member 2 being provided with a contact or brush f3 adapted to slidably engage a plate Contact 3 on`the member l for closing a circuit.

The brush is secured to one end of a carry- `ing member 5 by means of a rivet 26, the other end of member 5 being turned up to provide a hook 6 which loosely works in an opening l through one end of a member 8, the other end of said member being secured to a binding post 9 and therefore held rigid. The brush carrying member 5 is reduced inwidth to provide the portion for forming hook and also to provide a thrust shoulder iii on each side of the hook, the

yshoulders lll being provided in a portion of memwber 5 outside `oi that which is distorted to form hook 6 so as to obtain maximum resistance against distortion of said member when subject hand, as viewed in Fig. 1 of the drawing, as will be hereinafter described. The member 8 is VK.provided on` eachside with a depending thrust lug applied rby` contact plate 3` to the brush i in the opening 1 member 8 on Ythe edge of opening I.

arm secured in the member 2 below the lower end of spring I8 extends through the opening II and slot I2, and is provided with another arm adapted to engage the member 5 for limiting outward movement of said member by spring Ill.

The member 2 may be carried by the housing of a train wire coupling (not shown), while the member I may be carried by a movable member or slide in the train wire coupling, so that the member VI is adapted to move relatively to the member 2.

In the drawing the members I and 2 are shown in their circuit closing position. In order to open the circuit controlled through the engagement of the contact brush 4 and contact plate 3, the member I is moved toward the left hand relative to the member 2. Through the medium of the hook 6, the brush 4 is dragged across the contact plate 3 until the contact plate is moved out of engagement with said brush, at which time the spring I0 moves the brush outwardly until the member 5 engages the outer arm of the stop member I3.

If it is desired to close the circuit through the contact brush 4 and contact plate 3, the member I is moved towards the right hand and when the contact plate 3 engages the brush 4, the brush and brush carrying member 5 are also moved toward the right hand until the shoulders I4 engage lugs I5 on the support member 8, under which condition the outer surface of the hook 6 is free of or does not engage the member 8 in the Further movement of the contact plate 3 against the brush 4 then acts to displace the brush 4 in a downwardly direction, the force thus applied through member 5 to lugs I5 tending to cause the line contact between shoulders I4 and lugs I5 to shift downwardly, such downward shifting being limited however by the engagement of the inner surface of the hook 6 with After the brush 4 is thus displaced suiciently, the contact plate 3 moves over the top of said brush to the circuit closed position, as shown in'Fig. 1.

The movement of the contact plate 3 into circuit closing engagement wth thebrush 4 occurs substantially instantaneously, so that the brush 4,

carrying member 5 and member 8 are subjected to such 'forces as to tend to cause distortion particularly of the members 5 and 8. To prevent such distortion, these members are made as rugged as possible in view of the limited space available and they are also made of material having high compressive strength, such as steel. In addition to the above however, the shouldersl I4 on the brush carrying member 5 are formed in a portion of said member which is not distorted in forming hook 6, so that when compressive force is applied to the portion of said member adjacent hook 6, said force acts in a straight line through said portion of said member and the shoulders I4 against lugs I5, thereby obtaining maximum resistance to bending of said member 5.

Upon moving contact plate 3 into circuit closthe brush 4 is adapted to adjust itself to said contact plate in case of misalignment of either said brush or plate with respect' to each other. This adjustment is obtained by the shifting of the line of contact between shoulders I4 and lugs I5 either during the downward movement of said shoulders on said lugs or after engagement of the inner surface of hook 6 with member 8 within the opening 'I.

Y In either case, the brush 4 and carrying member 5 turn axially around an axis substantially parallel to the line of the direction of force applied by contact plate 3 to brush 4, and during this turning, contact is maintained between both of the shoulders I4 and their respective lugs I5. This axial turning of the member 5 is very free, and due to the face of lugs I5 engaged by shoulders I4 being formed at right angles to the direction of line of force applied by contact plate 3 t0 brush 4, the member 5 is maintained substantially, squarely in working alignment with member 8, that is, during such turning movement of member 5, the axis of member 5 is maintained square with respect to a plane passing vertically through the center of member 8,'as viewed in Fig. 1 of the drawing, thereby substantially equally dividing between shoulders I4 and their respective lugs I5 and squarely applying to the above described face of said lugs, the force applied to member 5.

- If the face of lugs I5 engaged by shoulders I4 were formed at any angle other than a right angle as above described, then the advantages of applicants construction would be substantially lost, for if the brush 4 should have to turn to compensate for misalignment of contacts, either one shoulder I4 or the other would tend to turn away from or undesirably bind against its respective lug, according to the character of such misalignment, with the result that the brush 4 and carrying member 5 would move out of square working alignment with the lugs I5 on member 8, and such action wouldtend to promote binding and possible distortion and breakage particularly of the members 5 and 8.

As hereinbefore described, the members 5 and 8 are preferably made of material, such as steel, on account of its strength, and are therefore poor electrical conductors. In order to obtain a path of high electrical conductivity between the contact 4 and terminal clip 22, shunts, made of ma.- terial such as copper, are provided around the members 5 and 8 connecting said contact to said terminal clip.

One shunt consists of two copper tips I8 and I9 connected by two flexible, and preferably strand- The tip I 8 is riveted against ber 8, where said member ts over the binding post 9, by means of a copper clip 2 I. A terminal tip 22 is then mounted on top of the clip 2l, and the tips 22 and I9, clip 2I and member 8 are then iirmly clamped together and in tight engagement with the insulating block 2 by means of a nut 23 having screw-threaded engagement on the binding post 9. A lock nut 24 is provided to prevent the holding nut 23 from becoming loose.

It will now be evident that the shunt consisting of tip I8, cables I'I and tip I9, and the shunt clip 2| connecting tip I9 to the terminal tip 22 provides a path of high electrical conductivity from the brush contact 4 directly to the terminal tip 22, so that neither the hinge-like joint between members 5 and 8 nor the fact that said members are made of steel will affect the continuity or conductivity of the circuit closed by way of the switch finger.

The shunt cables I1 are sufficiently long to prevent being placed under tension at any time gether, as indicated in Figs. l, 3 and 4, in order to betterY confine said cables to the limited space between the members and 8 and the insulating block 2.

Before mounting the member 8 and cable tip I9 on the binding post 9, said member and tip are firmly clamped together by means of the shunt clip 2|. This is very desirable in that it holds the various parts of the iinger together forming what may be termed a unitary structure which facilitates mounting and removal of the linger structure upon and from the insulating block 2.

The brush 4 is manufactured with a pin 20, as shown in Figs. 10 and 11, and after the assembly of the brush 4 with the member 5 and the cable tip I 8, the end of the pin is riveted down. The member 5 is provided with a square opening 25, as shown in Fig. 12, and the cable tip I8 is provided with a like square opening 26, as shown in Fig. 13. The square openings and 26 are suciently large for'the insertion of pin 20 and during the riveting process, the pin 20 is upset or pushed out into the openings 25 and 26 so as to firmly lock the brush i against turning on the member 5.

It will now be evident that I have provided an electrical shunt of high conductivity which is independent of the hinge joint in the contact nger and, therefore, the contact brush carrying members can be made of materials of adequate strength to withstand the tension and compression forces to which they are subjected in operation.

While one illustrative embodiment of the invention has been described in detail, it is not my intention to limit its scope -to that embodiment or otherwise than by the terms of the appended claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. The combination with an electrical terminal post, of a flexible contact mechanism adapted to be applied to said terminal post as a unit and removable from said terminal post as a unit, said mechanism comprising a support member adapted to be applied to said terminal post and having in one end an opening, a contact member having at one end a hook disposed in said opening forming an open hinge, a lexible shunt element having one end secured to said contact member and the other end adapted to be f applied to said terminal post, and a U-shaped one end and the other end bent in the form of a. hook, a support member having at one end an opening adapted to loosely receive said hook, said hook being adapted to engage said support member within said opening for pulling said contact carrying member in one direction, two spaced lugs on said support member, and two spaced shoulders on said contact carrying member adapted to engage said lugs to resist endwise movement of said contact carrying member in the opposite direction, said shoulders being formed on said contact carrying member, one either side of said hook, and in a portion of said contact carrying member outside of the distorted portion including said hook.

3. An electrical contact mechanism comprising a contact carrying member having a contact at one end and the other end bent in the form of a hook, a support member having at one end an opening adapted to loosely receive said hook, said hook being adapted to engage said support member within said opening for pulling said contact carrying member in one direction, two spaced lugs on said support member, and two spaced shoulders on said contact carrying member adapted to engage said lugs to resist endwise movement of said contact carrying member in the opposite direction, said shoulders being slidable on said lugs to permit turning of said contact carrying member relative to said support member, the face of said lugs engaged by said shoulders being arranged at right angles to 'the direction of line of force applied to said contact whereby the turning of said contact carrying member is about an axis substantially parallel to said direction of line of force.

4. An electrical contact mechanism comprising a contact carrying member having a contact at one end and the other end bent in the form of a. hook, a support member having at one end an opening adapted to loosely receive said hook, said hook being adapted to engage said support member within said opening for pulling said contact carrying member in one direction, two spaced lugs on said support member, and two spaced shoulders on said contact carrying member adapted to engage said lugs to resist endwise movement of said contact carrying member in the opposite direction, said shoulders being slidable on said lugs to permit turning of said contact carrying member relative to said support member, the face of said lugs engaged by said shoulders being so arranged with respect to the direction of force applied to said Contact and urging said shoulders into engagement with said lugs as to maintain the contact carrying member squarely in working alignment with said support member upon said turning of said contact carrying member.

HARRY F. WOERNLEY. 

